Carrier substrate, laminate, and method for manufacturing electronic device

ABSTRACT

A carrier substrate to be used, when manufacturing a member for an electronic device on a surface of a substrate, by being bonded to the substrate, includes at least a first glass substrate. The first glass substrate has a compaction described below of 80 ppm or less. Compaction is a shrinkage in a case of subjecting the first glass substrate to a temperature raising from a room temperature at 100° C./hour and to a heat treatment at 600° C. for 80 minutes, and then to a cooling to the room temperature at 100° C./hour.

TECHNICAL FIELD

The present invention relates to a carrier substrate and, in particular,to a carrier substrate including a glass substrate exhibiting apredetermined compaction.

In addition, the present invention also relates to a laminate includingthe carrier substrate described above and a method for manufacturing anelectronic device.

BACKGROUND ART

In recent years, devices (electronic devices) such as photovoltaicbatteries (PV), liquid crystal display panels (LCD), and organic ELdisplay panels (OLED) have become thinner and lighter, and the glasssubstrates used for these devices have been made thinner. When thestrength of the glass substrate is insufficient due to thinning,handleability of the glass substrate in the device manufacturing stepsdeteriorates.

Recently, a method for coping with the problem described above wasproposed in which a glass laminate in which a glass substrate and acarrier substrate are laminated is prepared and a member for anelectronic device such as a display device is formed on the glasssubstrate of the laminate, and then the carrier substrate is separatedfrom the glass substrate (for example, PTL 1). Reusing the separatedcarrier substrate as a carrier substrate for manufacturing a displaydevice was also considered.

CITATION LIST Patent Literature

PTL 1: WO 2007/018028

SUMMARY OF INVENTION Technical Problem

Meanwhile, recently, with demands for higher performance of electronicdevices, it is desired to perform processing under higher temperatureconditions (for example, 500° C. or more) when manufacturing electronicdevices. In addition, as described above, it is desirable that thecarrier substrate is reused a plurality of times.

The present inventors examined the manufacturing of an electronic deviceby repeatedly using the carrier substrate described in PTL 1 in themanufacturing of an electronic device involving a high temperaturetreatment. Specifically, repeated high temperature treatment of a glasssubstrate was simulated by using computer simulation assuming such aprocess is performed that a laminate including the carrier substratedescribed in PTL 1 is applied to the manufacturing of an electronicdevice involving a high temperature treatment and then the carriersubstrate is peeled and the carrier substrate is reused to manufacturean electronic device.

As a result, in a case where the electronic device is manufactured byreusing the carrier substrate, it was found that there is a concern thatpattern shifting or the like is likely to occur in the electronic deviceand the yield of the electronic device may be lowered.

The present invention is made in view of the above problems and anobject thereof is to provide a carrier substrate for which, even whenreused a plurality of times to manufacture electronic devices, themanufacturing yield of the electronic device is excellent.

In addition, another object of the present invention is to provide alaminate including the carrier substrate described above, and a methodfor manufacturing an electronic device using the laminate.

Solution to Problem

As a result of intensive research to solve the problem described above,the present inventors found that it is possible to solve the problemsdescribed above by using a carrier substrate including a glass substrateexhibiting a predetermined compaction, and completed the presentinvention.

That is, a first aspect of the present invention is a carrier substrateto be used, when manufacturing a member for an electronic device on asurface of a substrate, by being bonded to the substrate, the carriersubstrate including at least a first glass substrate, in which the firstglass substrate has a compaction described below of 80 ppm or less.

Compaction: a shrinkage in a case of subjecting the first glasssubstrate to a temperature raising from a room temperature at 100°C./hour and to a heat treatment at 600° C. for 80 minutes, and then to acooling to the room temperature at 100° C./hour.

In addition, in the first aspect, the compaction is preferably 70 ppm orless.

In addition, in the first aspect, the first glass substrate preferablyhas a strain point of 700° C. or more.

In addition, in the first aspect, the first glass substrate preferablyincludes a glass containing, in terms of mass percentages based onoxides, the following: SiO₂: 50% to 73%

Al₂O₃: 10.5% to 24%

B₂O₃: 0% to 5%

MgO: 0% to 10%

CaO: 0% to 14.5%

SrO: 0% to 24%

BaO: 0% to 13.5%

MgO+CaO+SrO+BaO: 8% to 29.5%

In addition, the first aspect preferably further includes an adhesivelayer arranged on the first glass substrate.

A second aspect of the present invention is a laminate including thecarrier substrate according to the first aspect; and a substratearranged on the carrier substrate. In addition, in the second aspect,the substrate is preferably a second glass substrate.

A third aspect of the present invention is a method for manufacturing anelectronic device, including a member forming step of forming a memberfor an electronic device on a surface of the substrate of the laminateaccording to the second aspect to obtain a member for an electronicdevice-attached-laminate; and a separating step of removing the carriersubstrate from the member for an electronic device-attached-laminate toobtain an electronic device having the substrate and the member for anelectronic device.

In addition, in the third aspect, the member for an electronic devicepreferably includes a low-temperature polysilicon (LTPS).

In addition, the third aspect preferably further includes a step havinga process temperature of 450° C. or more in forming the member for anelectronic device.

Advantageous Effects of Invention

According to the present invention, it is possible to provide a carriersubstrate for which, even when reused a plurality of times tomanufacture electronic devices, the manufacturing yield of theelectronic device is excellent.

In addition, according to the present invention, it is also possible toprovide a laminate including the carrier substrate and a method formanufacturing an electronic device using the laminate.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic cross-sectional view of one embodiment of acarrier substrate according to the present invention.

FIG. 2 is a schematic cross-sectional view of one embodiment of alaminate according to the present invention.

FIG. 3 is a schematic cross-sectional view of another embodiment of thelaminate according to the present invention.

FIG. 4 (A) of FIG. 4 and (B) of FIG. 4 are schematic cross-sectionalviews illustrating an embodiment of a method for manufacturing amember-attached-substrate according to the present invention in order ofsteps. (A) of FIG. 4 is a schematic cross-sectional view of a member foran electronic device-attached-laminate 22 obtained in a member formingstep, and (B) of FIG. 4 is a schematic cross-sectional view of amember-attached-substrate 24 obtained in a separating step and a carriersubstrate 10.

DESCRIPTION OF EMBODIMENTS

A description will be given below of embodiments for carrying out thepresent invention with reference to the drawings; however, the presentinvention is not limited to these following embodiments, and variousmodifications and substitutions to the following embodiments arepossible within a range not departing from the scope of the presentinvention.

One of the characteristics of the carrier substrate of the presentinvention is the point of including a glass substrate exhibitingpredetermined compaction.

The present inventors studied the reason why the yield of the electronicdevice decreases when the carrier substrate is reused a plurality oftimes, and found that the yield is influenced by the heat shrinkage(compaction) of the carrier substrate.

First, manufacturing an electronic device usually includes a process offorming a fine pattern by using a mask. The shape of the mask (the sizeof the opening) is often formed in consideration of the heat shrinkageof the workpiece during the heat treatment. Therefore, when anelectronic device is manufactured by using a laminate including acarrier substrate, the shape of the mask is designed based on the sizeof the laminate heat-shrunk in the first manufacturing of the electronicdevice.

The present inventors found that after manufacturing an electronicdevice by using a carrier substrate including a glass substrate (AN100manufactured by Asahi Glass Co., Ltd.) which is a support platedescribed in PTL 1, when manufacturing an electronic device by using thecarrier substrate again, since the carrier substrate further undergoesheat shrinkage, pattern deviation is likely to occur when an electronicdevice is manufactured by using the already manufactured mask. In otherwords, it was found that the substrate arranged thereon also shrinks dueto the heat shrinkage of the carrier substrate, resulting in positionalshifting of the pattern to be formed, thereby lowering the manufacturingyield of the electronic device.

The present inventors found the above cause and examined solutionmethods thereof and, as a result, found that when a glass substratehaving a predetermined compaction value when processed underpredetermined heating conditions is used, even in the second time ofmanufacturing an electronic device and thereafter, it is possible tosuppress the heat shrinkage of the glass substrate (in other words, thecarrier substrate), and as a result, the manufacturing yield of theelectronic device is excellent.

The carrier substrate of the present invention may have at least a firstglass substrate having predetermined characteristics, but the carriersubstrate illustrated in FIG. 1 is preferably used. FIG. 1 is aschematic cross-sectional view of a carrier substrate according to afirst embodiment of the present invention.

As illustrated in FIG. 1, the carrier substrate 10 is a laminate havinga first glass substrate 12 and an adhesive layer 14 arranged on thefirst glass substrate 12. In the adhesive layer 14, a surface 14 b is incontact with the first main surface of the first glass substrate 12, andno other material is in contact with a surface 14 a.

In general, as illustrated in FIG. 2, the carrier substrate 10 islaminated such that the surface 14 a of the adhesive layer 14 and asubstrate 16 are in contact with each other, so as to be used in amember forming step of manufacturing a member for an electronic devicesuch as a liquid crystal panel on the substrate 16.

FIG. 2 is a schematic cross-sectional view of one embodiment of thelaminate according to the present invention.

As illustrated in FIG. 2, a laminate 100 is a laminate having a layer ofthe first glass substrate 12, a layer of the substrate 16, and theadhesive layer 14 present therebetween. One surface of the adhesivelayer 14 is in contact with the layer of the first glass substrate andthe other surface thereof is in contact with a first main surface 16 aof the substrate 16. Here, the substrate 16 is peelably laminated on theadhesive layer 14.

The carrier substrate 10 formed of the first glass substrate 12 and theadhesive layer 14 functions as a reinforcing plate for reinforcing thesubstrate 16 in a member forming step of manufacturing a member for anelectronic device such as a liquid crystal panel.

The laminate 100 is used up to a member forming step to be describedbelow. That is, the laminate 100 is used until a member for anelectronic device such as a liquid crystal display device is formed on asecond main surface 16 b of the substrate 16. Thereafter, the laminateon which the member for an electronic device is formed is separated intothe carrier substrate 10 and a member-attached-substrate, and thecarrier substrate 10 is not a portion which forms the electronic device.A new substrate 16 is laminated on the carrier substrate 10 and theresult is able to be reused as a new laminate 100.

Here, the adhesive layer 14 is fixed on the first glass substrate 12 andthe substrate 16 is peelably laminated (adhered) on the adhesive layer14 of the carrier substrate 10. In the present invention, fixing andpeelably laminating (adhering) are different in peel strengths (that is,the stress required for peeling) and fixing means that the peel strengthis greater than that of the adhering. In other words, the peel strengthat the interface between the adhesive layer 14 and the first glasssubstrate 12 is larger than the peel strength at the interface betweenthe adhesive layer 14 and the substrate 16. That is to say that peelablelamination (adhesion) means that peeling is possible and that thepeeling is possible without causing a peeling at the fixed surface.

More specifically, when the interface between the first glass substrate12 and the adhesive layer 14 has a peel strength (x) and stress isapplied in the peeling direction exceeding the peel strength (x) at theinterface between the first glass substrate 12 and the adhesive layer14, the interface between the first glass substrate 12 and the adhesivelayer 14 is peeled. When the interface between the adhesive layer 14 andthe substrate 16 has a peel strength (y) and stress is applied in thepeeling direction exceeding the peel strength (y) at the interfacebetween the adhesive layer 14 and the substrate 16, the interfacebetween the adhesive layer 14 and the substrate 16 is peeled.

In the laminate 100 (which also means the member for an electronicdevice-attached-laminate described below), the peel strength (x) ishigher than the peel strength (y). Accordingly, when stress is appliedto the laminate 100 in a direction to separate the first glass substrate12 and the substrate 16, the laminate 100 is peeled at the interfacebetween the adhesive layer 14 and the substrate 16 to separate into thesubstrate 16 and the carrier substrate 10.

The peel strength (x) is preferably sufficiently higher than the peelstrength (y). Increasing the peel strength (x) means that the adhesiveforce of the adhesive layer 14 to the first glass substrate 12 isincreased, and it is possible to maintain a higher adhesive forcerelative to that to the substrate 16 after the heat treatment.

A method for increasing the adhesive force of the adhesive layer 14 tothe first glass substrate 12 is not particularly limited and examplesthereof include, as described below, a method of curing the curableresin on the first glass substrate 12 to form the predetermined adhesivelayer 14. It is possible to form the adhesive layer 14 bonded to thefirst glass substrate 12 with high bonding force by using the adhesiveforce during curing. On the other hand, the bonding force of theadhesive layer 14 to the substrate 16 is usually lower than the bondingforce generated at the time of curing. Accordingly, carrying out acuring treatment (heat treatment) on the curable resin layer on thefirst glass substrate 12 to form the adhesive layer 14 and thenlaminating the substrate 16 on the surface of the adhesive layer 14makes it possible to manufacture the laminate 100 which satisfies thedesired peeling relationship.

In FIG. 1, the carrier substrate having the first glass substrate andthe adhesive layer is illustrated in detail, but the present inventionis not limited to this embodiment, and an adhesive layer may not beprovided as long as it is possible to peelably laminate the substrate.That is, the carrier substrate may be one formed of a first glasssubstrate.

In the case of this embodiment, as illustrated in FIG. 3, a substrate116 is arranged on a first glass substrate 112 to form a laminate 110.

In the present embodiment, the surface roughness (Ra) of the surface (asurface 112 a in FIG. 3) on the side of the first glass substrate 112 incontact with the substrate 116 is preferably 2.0 nm or less, and morepreferably 1.0 nm or less. The lower limit value is not particularlylimited, but 0 is the most preferable. In the range described above,adhesion with the substrate 116 is further improved, it is possible tofurther suppress positional shifting of the substrate 116 and the like,and the substrate 116 is also excellent in peelability.

The surface roughness (Ra) is measured according to JIS B 0601 (revised2001).

A detailed description will be given below of each layer (the firstglass substrate 12, the substrate 16, the adhesive layer 14) forming thecarrier substrate 10 and the laminate 100, and thereafter a detaileddescription will be given of the method for manufacturing a carriersubstrate, a laminate, and a member-attached-substrate.

Since the first glass substrate 112 and the substrate 116 in thelaminate 110 have the same structure as the first glass substrate 12 andthe substrate 16, description thereof is omitted.

<First Glass Substrate 12>

The first glass substrate 12 supports and reinforces the substrate 16and, in a member forming step (step of manufacturing a member for anelectronic device) described below, prevents deformation, scratching,breaking, or the like of the substrate 16 when manufacturing the memberfor an electronic device.

The first glass substrate 12 is a glass substrate having a compaction(compaction value) of 80 ppm or less in a case of a heat treatment at600° C. for 80 minutes. Here, in terms of a superior manufacturing yieldof electronic devices (also simply referred to below as “the effect ofthe present invention is superior”), the compaction is preferably 70 ppmor less, more preferably 60 ppm or less, and even more preferably 50 ppmor less. The lower limit is not particularly limited, but is often 20ppm or more due to the characteristics of the glass.

In a case where the compaction exceeds 80 ppm, the manufacturing yieldof the electronic device is inferior.

The compaction described above is the glass heat shrinkage generated byrelaxation of the glass structure during heat treatment. In the presentinvention, the compaction means the shrinkage (ppm) of the indentationinterval distance in a case of stamping two indentations atpredetermined intervals on the surface of a glass substrate, thenheating the glass substrate to raise the temperature from roomtemperature to 600° C. at 100° C./hour, maintaining it at 600° C. for 80minutes, and then cooling it to room temperature at 100° C./hour.

It is possible to measure the compaction in the present invention by thefollowing method.

The surface of the glass substrate is polished to obtain a 100 mm×20 mmsample. Point-like indentations are stamped on the surface of the sampleat two positions in the long-side direction at an interval A (A=95 mm).

Next, the sample is heated from room temperature to 600° C. at atemperature-raising rate of 100° C./hour (=1.6° C./min), held at 600° C.for 80 minutes, and then cooled to room temperature at atemperature-lowering rate of 100° C./hour. Then, the distance betweenthe indentations is measured again, and this distance is taken as B. Thecompaction is calculated from A and B obtained in this manner using thefollowing equation. Here, A and B are measured by using an opticalmicroscope.

Compaction [ppm]=(A−B)/A×10⁶

Although the range of the strain point of the first glass substrate 12is not particularly limited, it is preferably 700° C. or more, and morepreferably 710° C. or more, from the viewpoint of the superior effectsof the present invention. However, since a problem occurs in glassmolding when the strain point is excessively high, it is preferably 770°C. or less. It is more preferably 760° C. or less, and even morepreferably 750° C. or less.

The strain point is a temperature at which a viscous flow of glass ispractically impossible, corresponds to the lower limit temperature inthe slow cooling range, and is a temperature at which the viscositycorresponds to 10¹⁴⁵ dPa·s {poise}. The strain point is measured byusing the fiber elongation method set out in JIS-R 3103 (2001) andASTM-C 336 (1971).

The composition of the first glass substrate 12 is not particularlylimited, but in terms of the superior effect of the present invention,the glass matrix composition is preferably in the following range interms of mass percentage based on oxides.

SiO₂: 50% to 73%

Al₂O₃: 10.5% to 24%

B₂O₃: 0% to 5%

MgO: 0% to 10%

CaO: 0% to 14.5%

SrO: 0% to 24%

BaO: 0% to 13.5%

MgO+CaO+SrO+BaO: 8% to 29.5%

Next, a description will be given of the composition range of eachcomponent.

When SiO₂ is less than 50% (in terms of mass percentage based on oxides,the same applies below unless otherwise specified), the strain pointdoes not rise sufficiently and the thermal expansion coefficientincreases and the density rises, thus 50% or more is preferable. It ismore preferably 53% or more, even more preferably 55% or more, andparticularly preferably 57% or more. When it exceeds 73%, themeltability decreases and the defoaming property decreases, thus it ispreferably 73% or less. It is more preferably 70% or less, even morepreferably 67% or less, and particularly preferably 65% or less.

Although Al₂O₃ suppresses the phase separation property of the glass,decreases the coefficient of thermal expansion, and raises the strainpoint, this effect does not appear at below 10.5%, and other componentswhich increase expansion are increased, thus, the thermal expansionbecomes large as a result. It is preferably 10.5% or more, morepreferably 15% or more, and even more preferably 17% or more. When itexceeds 24%, there is a concern that the meltability of the glass maydeteriorate and the devitrification temperature may rise, thus it ispreferably 24% or less, and more preferably 22% or less.

B₂O₃ improves the dissolution reactivity of the glass and lowers thedevitrification temperature and thus is able to be added at 0% or moreand 5% or less. In order to obtain the above effects, it is preferably0.1% or more. However, when it is excessive, the strain point becomeslow. Therefore, it is preferably 5% or less, and more preferably 3% orless.

MgO has the characteristics of not increasing expansion among alkalineearths and not excessively lowering the strain point and also improvesmeltability.

Here, the MgO content is preferably 0% or more and 10% or less, and morepreferably 1% or more. When it exceeds 10%, there is a concern that thedevitrification temperature may rise, thus it is preferably 10% or less,more preferably 7% or less, and even more preferably 6% or less.

CaO has a characteristic of not increasing the expansion among thealkaline earths next to MgO and not excessively lowering the strainpoint and also improves meltability.

Here, the CaO content is preferably 0% or more and 14.5% or less, morepreferably 1% or more, and even more preferably 3% or more. When itexceeds 14.5%, there is a concern that the devitrification temperaturemay rise. It is more preferably 10% or less, and even more preferably 7%or less.

SrO is an optional component which improves meltability withoutincreasing the devitrification temperature of the glass.

Here, the SrO content is preferably 0% or more and 24% or less, and morepreferably 1% or more. When it exceeds 24%, there is a concern that theexpansion coefficient may increase. It is more preferably 12% or less,and even more preferably 9% or less.

Although BaO is not essential, it can be included to improve themeltability and to improve the devitrification resistance. However, whenit is excessive, the expansion and density of the glass increaseexcessively, thus, it is preferably 13.5% or less, more preferably 12%or less, and even more preferably 10% or less.

Here, in a case where the density is a problem in particular, the BaOcontent should be small, preferably 5% or less, preferably 1% or less,more preferably 0.5% or less, and particularly preferably substantiallynot contained. The expression “substantially not contained” means notcontained other than unavoidable impurities.

On the other hand, in a case where importance is given to thedevitrification resistance, it is preferably 1% or more, more preferably3% or more, and even more preferably 5% or more.

When the total amount of MgO, CaO, SrO, and BaO is less than 8%, themeltability is poor. It is preferably 8% or more, and more preferably10% or more. It is even more preferably 12% or more, and particularlypreferably 14% or more. When it exceeds 29.5%, there is a concern ofcausing a problem that the thermal expansion coefficient cannot be madesmall, thus it is preferably 29.5% or less, more preferably 25% or less,even more preferably 23% or less, and particularly preferably 21% orless.

As other components, it is possible to add components for adjusting thephysical properties and fining agents as long as the features of thepresent invention are not impaired. Examples of components for adjustingthe physical properties include Fe₂O₃, ZnO, ZrO₂, TiO₂, Nb₂O₅, Ta₂O₅,Y₂O₃, La₂O₃, Gd₂O₃, and P₂O₅, and examples of fining agents includeSnO₂, SO₃, Cl, F, and the like. In each case, it is possible for theabove to be contained in the range of less than 1%.

Alkali metal oxides such as Li₂O, Na₂O and K₂O may be mixed asunavoidable impurities of raw materials or added to promote melting.These cause contamination by alkali ions in the TFT manufacturing step,and as a result, there is a possibility of causing the TFTcharacteristics to deteriorate. Therefore, it is preferable that thecontent thereof is as little as possible. Specifically, they arepreferably 0.1% or less. They are more preferably 0.08% or less, evenmore preferably 0.05% or less, and particularly preferably 0.03% orless.

Since As₂O₃, PbO and CdO adversely affect the environment, thesecomponents are substantially not contained.

It is preferable that the glass used for the first glass substrate 12 orthe first glass substrate 112 has a high Young's modulus in order toreduce bending during transport of the laminated substrate. It ispreferably 77 GPa or more, more preferably 80 GPa or more, andparticularly preferably 82 GPa or more.

In addition, if the glass used for the first glass substrate 12 or thefirst glass substrate 112 is scratched, when the recycling is performed,there is a possibility that the strength will be reduced or unevennesswill occur in ultraviolet irradiation described below. Therefore, it ispreferable that the Vickers hardness of the glass of the first glasssubstrate 12 or the first glass substrate 112 is high. It is preferably580 or more, more preferably 590 or more, and even more preferably 600or more.

The step of manufacturing an electronic device such as a liquid crystaldisplay or an OLED display using the glass used for the first glasssubstrate 12 or the first glass substrate 112 may include a step ofirradiating with, for example, ultraviolet light through the first glasssubstrate 12 so as to cure the liquid crystal alignment film or destroythe bond at the resin-glass interface and facilitate peeling. Therefore,it is preferable that the glass has high ultraviolet transmittance. Theexternal transmittance (transmittance including reflection on the frontand back surfaces) of 300 nm is preferably 40% or more in terms of 0.5mm thickness conversion. It is more preferably 50% or more, even morepreferably 60% or more, and particularly preferably 70% or more.

The thickness of the first glass substrate 12 may be thicker or thinnerthan the substrate 16, but is often thinner than the substrate 16. Thethickness of the first glass substrate 12 is preferably selected basedon the thickness of the substrate 16, the thickness of the adhesivelayer 14, and the thickness of the laminate 100. For example, in a casewhere a current member forming step is designed to process a substratehaving a thickness of 0.5 mm and the sum of the thickness of thesubstrate 16 and the thickness of the adhesive layer 14 is 0.1 mm, thethickness of the first glass substrate 12 is set to 0.4 mm. In a typicalcase, the thickness of the first glass substrate 12 is preferably 0.2 to0.5 mm, and is preferably thicker than the substrate 16.

The method for manufacturing the first glass substrate 12 is notparticularly limited, as long as a glass substrate exhibiting thecompaction described above can be obtained. Among such methods, in viewof easy adjustment of compaction, a manufacturing method having amelting step of dissolving a glass raw material to obtain molten glass,a forming step of forming the molten glass obtained by the melting stepinto a plate-like glass ribbon, and a slow cooling step of graduallycooling the glass ribbon formed in the forming step is preferable.

In the melting step, the glass raw material is melted to obtain moltenglass. For example, a glass raw material is prepared so as to obtain acomposition of the glass plate to be obtained, the glass raw material iscontinuously charged into a melting furnace, and heated to about 1450 to1650° C. to obtain molten glass.

In the forming step, the molten glass obtained by the melting step isformed into a plate-like glass ribbon (ribbon-shaped glass plate). Morespecifically, it is formed into a glass ribbon having a predeterminedthickness by a float method or a fusion method.

In the slow cooling step, the plate-like glass ribbon obtained by theforming step is gradually cooled. In order to adjust to the compactionin the predetermined range described above, a method of controlling thecooling rate in this slow cooling step is preferable. It is possible toadjust the average cooling rate in a range of, for example, 15 to 600°C./min. It is preferably 20 to 400° C./min, more preferably 30 to 300°C./min, and even more preferably 30 to 100° C./min, from the viewpointof the superior effect of the present invention.

Here, in a case where the surface temperature of the ribbon-shaped glassplate is TH (° C.), room temperature is TL (° C.), and the time untilthe surface temperature of the ribbon-shaped glass plate is cooled fromTH to TL is t (min), the average cooling rate is the rate indicated by(TH-TL)/t.

In addition, the specific cooling means is not particularly limited, andmay be a cooling method known in the related art. Examples thereofinclude a method using a heating furnace having a temperature gradient.

<Substrate>

In the substrate 16, the first main surface 16 a is in contact with theadhesive layer 14 and the member for an electronic device is provided onthe second main surface 16 b on the opposite side to the adhesive layer14 side. That is, the substrate 16 is a substrate used for forming anelectronic device described below.

The type of the substrate 16 is not particularly limited, and examplesthereof include a glass substrate, a resin substrate, a metal substrate,and the like.

In a case where a glass substrate (also referred to below as a secondglass substrate) is used as the substrate 16, the type of the secondglass substrate may be a general one and examples thereof include aglass substrate for a display device such as an LCD or an OLED. Thesecond glass substrate is excellent in chemical resistance and moisturepermeation resistance and has a low heat shrinkage. As an index of theheat shrinkage, the coefficient of linear expansion specified in JIS R3102 (revised 1995) is used.

The second glass substrate is obtained by melting the glass raw materialand forming the molten glass into a plate shape. The forming method maybe a general method, and for example, a float process, a fusion process,a slot down draw process, or the like is used. In addition, it is alsopossible to form and obtain the second glass substrate, which has aparticularly small thickness, with a method of heating a glasstemporarily formed into a plate shape to a formable temperature andthinning by stretching with a means such as stretching (a redrawmethod).

The type of the glass of the second glass substrate is not particularlylimited, but an oxide-based glass containing silicon oxides as a maincomponent, such as alkali-free borosilicate glass, borosilicate glass,soda-lime glass, high silica glass, and the like is preferable. As theoxide-based glass, a glass having a silicon oxide content of 40 to 90%by mass in terms of oxide is preferable.

As the glass of the second glass substrate, a glass suitable for thetype of member for an electronic device and manufacturing steps thereofis adopted. For example, a glass substrate for a liquid crystal panel isformed of a glass (alkali-free glass) substantially not including alkalimetal components (provided that alkaline earth metal components arenormally included) since the dissolution of alkali metal components islikely to affect the liquid crystal. In this manner, the glass of thesecond glass substrate is appropriately selected based on the type ofthe device to be applied thereto and the manufacturing steps thereof.Here, “substantially not including alkali metal components” means thatthe content of the alkali metal components is 0.1% by mass or less.

In a case where a resin substrate is used as the substrate 16 or thesubstrate 116, the type of resin constituting the resin substrate is notparticularly limited, but a polyimide resin is preferable from theviewpoint of heat resistance.

From the viewpoint of reducing the thickness and/or weight of thesubstrate 16, the thickness of the substrate 16 is preferably 0.3 mm orless, more preferably 0.15 mm or less, and even more preferably 0.10 mmor less. In a case where it is 0.3 mm or less, it is possible to impartgood flexibility to the substrate 16. In a case where it is 0.15 mm orless, it is possible to wind the substrate 16 into a roll shape.

In addition, the thickness of the substrate 16 is preferably 0.03 mm ormore for reasons such as ease of manufacturing of the substrate 16 andease of handling of the substrate 16.

In a case where a resin substrate such as polyimide is used, there is amethod in which a polyimide precursor is directly coated on the firstglass substrate 112 and a heat treatment is performed at a hightemperature of 400° C. to 500° C. to conduct curing. In this case, thethickness of the substrate 116 is preferably 0.1 mm or less, and morepreferably 0.05 mm or less. On the other hand, it is preferably 0.001 mmor more, more preferably 0.005 mm or more, and even more preferably 0.01mm or more, in order to maintain the strength when peeled as a device.

Furthermore, the glass of the first glass substrate 112 in a case wherethe device is manufactured by such steps is required to have highultraviolet transmittance. This is for irradiating with ultraviolet raysfrom the side of the first glass substrate 112 when peeling thesubstrate 116 directly formed on the first glass substrate 112.Therefore, regardless of plate thickness, as an external transmittanceat a wavelength of 300 nm, the ultraviolet transmittance of the glass ofthe first glass substrate 112 is preferably 40% or more, more preferably50% or more, even more preferably 60% or more, and particularlypreferably 70% or more.

The plate thickness of the first glass substrate 112 is not particularlylimited, but when the plate thickness becomes excessively thin,deflection becomes large and problems occur in transportation, and thusit is preferably 0.4 mm or more, and more preferably 0.5 mm or more. Onthe other hand, it is excessively thick, the weight of the substratebecomes excessively large and the load of the conveying device becomeslarge, and thus it is preferably 1.0 mm or less, and more preferably 0.7mm or less.

<Adhesive Layer>

The adhesive layer 14 prevents positional shifting of the substrate 16until the operation of separating the substrate 16 and the first glasssubstrate 12 is performed and prevents breakage of the substrate 16 andthe like due to a separation operation. The surface 14 a of the adhesivelayer 14 in contact with the substrate 16 is peelably laminated(adhered) on the first main surface 16 a of the substrate 16. Asdescribed above, the adhesive layer 14 is bonded to the first mainsurface 16 a of the substrate 16 with a weak bonding force, and the peelstrength (y) of the interface thereof is lower than the peel strength(x) of the interface between the adhesive layer 14 and the first glasssubstrate 12.

That is, when separating the substrate 16 and the first glass substrate12, peeling is performed at the interface between the first main surface16 a of the substrate 16 and the adhesive layer 14 and peeling is hardlyperformed at the interface between the first glass substrate 12 and theadhesive layer 14. Therefore, the adhesive layer 14 has a surfacecharacteristic in which it is in close contact with the first mainsurface 16 a of the substrate 16 and it allows easy peeling of thesubstrate 16. That is, the adhesive layer 14 is bonded to the first mainsurface 16 a of the substrate 16 with a certain degree of bonding forceto prevent positional shifting of the substrate 16 or the like and, atthe same time, bonded with a bonding force to such an extent that thesubstrate 16 is able to be easily peeled without the substrate 16 beingdestroyed when peeling it. In the present invention, the property of thesurface of the adhesive layer 14 of being able to be easily peeled isreferred to as peelability. On the other hand, the first main surface ofthe first glass substrate 12 and the adhesive layer 14 are bonded toeach other with a bonding force at which separation is relativelydifficult.

The type of the adhesive layer 14 is not particularly limited and may bean organic layer composed of a resin or the like, or an inorganic layer.Each case will be described in detail below.

(Organic Layer)

The organic layer is preferably a resin layer that includes apredetermined resin. The type of resin forming the resin layer is notparticularly limited, and examples thereof include a silicone resin, apolyimide resin, an acrylic resin, a polyolefin resin, a polyurethaneresin, a fluorine-based resin, and the like. It is also possible to mixand use several types of resins. Among these, a silicone resin, apolyimide resin, and a fluorine-based resin are preferable.

The silicone resin is a resin which includes a predeterminedorganosiloxy unit and is generally obtained by curing a curablesilicone. The curable silicones are classified into addition reactiontype silicones, condensation reaction type silicones, ultraviolet curingtype silicones, and electron beam curing type silicones according to thecuring mechanism thereof, and it is possible to use any of these. Amongthese, addition reaction type silicones or condensation reaction typesilicones are preferable.

As the addition reaction type silicone, it is possible to suitably use acurable composition which includes a main agent and a cross-linkingagent and which is curable in the presence of a catalyst such as aplatinum-based catalyst. The curing of the addition reaction typesilicone is promoted by a heat treatment. The main agent in the additionreaction type silicone is preferably an organopolysiloxane having analkenyl group (such as a vinyl group) bonded to a silicon atom (that is,an organoalkenylpolysiloxane, preferably straight-chain form), and analkenyl group or the like serves as a cross-linking point. Thecross-linking agent in the addition reaction type silicone is preferablyan organopolysiloxane having a hydrogen atom (a hydrosilyl group) bondedto a silicon atom (that is, an organohydrogenpolysiloxane, preferablystraight-chain form), and a hydrosilyl group or the like serves as across-linking point.

The addition reaction type silicone is cured by the addition reaction ofthe cross-linking points of the main agent and the cross-linking agent.From the viewpoint of superior heat resistance derived from thecross-linked structure, the molar ratio of hydrogen atoms bonded tosilicon atoms of the organohydrogenpolysiloxane with respect to thealkenyl groups of the organoalkenylpolysiloxane is preferably 0.5 to 2.

In the case of using an addition reaction type silicone, a catalyst (inparticular, a platinum group metal-based catalyst) may be further used,if necessary.

The platinum group metal-based catalyst (platinum group metal catalystfor hydrosilylation) is a catalyst for promoting and accelerating thehydrosilylation reaction between the alkenyl group in the organoalkenylpolysiloxane and the hydrogen atom in the organohydrogenpolysiloxane.Examples of the platinum group metal-based catalyst includeplatinum-based catalysts, palladium-based catalysts, and rhodium-basedcatalysts, in particular, the use as platinum-based catalysts ispreferable from the viewpoint of economy and reactivity.

As the condensation reaction type silicone, it is possible to suitablyuse a hydrolyzable organosilane compound as a monomer or a mixturethereof (monomer mixture) or a partially hydrolyzed condensate(organopolysiloxane) obtained by subjecting a monomer or monomer mixtureto a partial hydrolytic condensation reaction.

By using this condensation reaction type silicone and allowing ahydrolysis/condensation reaction (sol-gel reaction) to proceed, asilicone resin can be formed.

The polyimide resin is a resin having an imide structure and a resinobtained by a reaction of tetracarboxylic acids and diamines.

Although the structure of the polyimide resin is not particularlylimited, it is preferably formed of a repeating unit having a residue(X) of a tetracarboxylic acid and a residue (A) of a diamine representedby Formula (1) below.

In Formula (1), X represents a tetracarboxylic acid residue obtained byremoving a carboxy group from a tetracarboxylic acid, and A represents adiamine residue obtained by removing an amino group from a diamine.

In Formula (1), X is preferably formed of at least one kind of groupselected from the group consisting of the groups represented by Formulas(X1) to (X4) below.

Among these, in terms of excellent heat resistance of the polyimideresin, 50 mol % or more (preferably 80 to 100 mol %) of the total numberof X is more preferably at least one kind of group selected from a groupconsisting of the groups represented by the following Formulas (X1) to(X4). It is even more preferable that substantially all of the totalnumber of X (100 mol %) is formed of at least one kind of group selectedfrom the group consisting of the groups represented by the aboveFormulas (X1) to (X4).

In addition, A represents a diamine residue obtained by removing anamino group from a diamine and is preferably formed of at least one kindof group selected from the group consisting of the groups represented bythe following Formulas (A1) to (A8).

Among these, in terms of excellent heat resistance of the polyimideresin, 50 mol % or more (preferably 80 to 100 mol %) of the total numberof A is more preferably at least one kind of group selected from a groupconsisting of groups represented by the following Formulas (A1) to (A8).It is even more preferable that substantially all of the total number ofA (100 mol %) is formed of at least one kind of group selected from agroup consisting of the groups represented by the following Formulas(A1) to (A8).

It is also possible to use the polyimide shown above not only as anorganic layer, but also as a second substrate (substrate 116).

The thickness of the organic layer is not particularly limited, but itis preferably 1 to 100 μm, more preferably 5 to 30 μm, and even morepreferably 7 to 20 μm. This is because when the thickness of the organiclayer is in such a range, adhesion between the organic layer and thefirst glass substrate or the substrate is sufficient.

(Inorganic Layer)

The material constituting the inorganic layer is not particularlylimited, but it is preferable to include, for example, at least oneselected from a group consisting of oxides, nitrides, oxynitrides,carbides, carbonitrides, silicides, and fluorides. Among these, it ispreferable to include an oxide in terms of the peelability of thesubstrate 16 being superior.

Examples of oxides (preferably metal oxides), nitrides (preferably metalnitrides) and oxynitrides (preferably metal oxynitrides) include oxides,nitrides and oxynitrides of one or more kinds of elements selected fromSi, Hf, Zr, Ta, Ti, Y, Nb, Na, Co, Al, Zn, Pb, Mg, Bi, La, Ce, Pr, Sm,Eu, Gd, Dy, Er, Sr, Sn, In, and Ba.

More specifically, examples thereof include a silicon nitride oxide(SiN_(x)O_(y)), titanium oxide (TiO₂), indium oxide (In₂O₃), indiumcerium oxide (ICO), tin oxide (SnO₂), zinc oxide (ZnO), gallium oxide(Ga₂O₃), indium tin oxide (ITO), indium zinc oxide (IZO), zinc tin oxide(ZTO), gallium added zinc oxide (GZO), and the like.

Examples of carbides (preferably metal carbides) and carbonitrides(preferably metal carbonitrides) include carbides, carbonitrides andcarbonates of one or more kinds of elements selected from Ti, W, Si, Zr,and Nb. Examples thereof include silicon carbide oxide (SiCO), and thelike.

The carbide may be a so-called carbon material, and may be a carbideobtained by sintering a resin component such as a phenol resin, forexample.

Examples of silicide (preferably metal silicide) include silicide of oneor more kinds of elements selected from Mo, W and Cr.

Examples of fluorides (preferably, metal fluorides) include fluorides ofone or more kinds of elements selected from Mg, Y, La, and Ba. Forexample, examples thereof include magnesium fluoride (MgF₂) and thelike.

The thickness of the inorganic layer is not particularly limited, but ispreferably 5 to 5000 nm, and more preferably 10 to 500 nm from theviewpoint that the effect of the present invention is superior.

The surface roughness (Ra) of the surface of the inorganic layer incontact with the substrate 16 is preferably 2.0 nm or less, and morepreferably 1.0 nm or less. The lower limit value is not particularlylimited, but 0 is the most preferable. Within the range described above,adhesion with the substrate 16 is further improved, it is possible tofurther suppress positional shifting of the substrate 16 and the like,and the substrate 16 is also excellent in peelability.

Ra is measured in accordance with JIS B 0601 (revised 2001).

<Method for Manufacturing Carrier Substrate and Laminate>

The method for manufacturing the laminate 100 of the first embodiment ofthe present invention is not particularly limited and it is possible toadopt a known method, but in general, it includes an adhesive layerforming step of forming the adhesive layer 14 on the first glasssubstrate 12, and a laminating step of laminating the substrate 16 onthe adhesive layer 14 to obtain the laminate 100. Here, the adhesivelayer forming step described above corresponds to a carrier substratemanufacturing step.

Here, a detailed description will be given of the adhesive layer formingstep and the laminating step.

(Adhesive Layer Forming Step)

The adhesive layer forming step is a step of forming the adhesive layer14 on the first glass substrate 12. The method for forming the adhesivelayer 14 is not particularly limited, and it is possible to adopt aknown method, which varies depending on the type of the materialconstituting the adhesive layer 14.

For example, in a case where the adhesive layer 14 is an organic layer,examples of methods for preparing the organic layer include a method(coating method) of coating a curable resin composition which includes acurable resin onto the first glass substrate 12 and curing the curableresin composition to form the adhesive layer 14 fixed on the first glasssubstrate 12, a method (attachment method) of fixing a film shapedadhesive layer 14 to the surface of the first glass substrate 12, or thelike. Among others, the coating method is preferable in terms of theadhesion strength of the adhesive layer 14 to the first glass substrate12 being superior.

In the coating method, examples of a method for forming the curableresin composition layer on the surface of the first glass substrate 12include methods of coating curable resin compositions on a glasssubstrate. Examples of coating methods include a spray coating method, adie coating method, a spin coating method, a dip coating method, a rollcoating method, a bar coating method, a screen printing method, agravure coating method, and the like.

The curing method is not particularly limited, and the optimum curingconditions are selected depending on the resin to be used. Usually, as acuring method, a heat treatment is employed.

Here, in addition to the above, an organic layer may be prepared by aknown method.

For example, the method for preparing an adhesive layer that includes afluorine-based resin is not particularly limited and examples thereofinclude a method of preparing an adhesive layer by using a compositionincluding a fluorine-based resin or a method of preparing an adhesivelayer on the surface of the object by irradiating with a plasma using afluorine-based gas.

In addition, in a case where the adhesive layer 14 is an inorganiclayer, it is possible to adopt a known method as a method formanufacturing the inorganic layer. Examples thereof include a method ofproviding an inorganic layer formed of predetermined components on thefirst glass substrate 12 by, for example, a vapor deposition method, asputtering method or a CVD method. The inorganic layer obtained by theabove method is fixed on the first glass substrate 12 and the exposedsurface of the inorganic layer is able to be peelably adhered to thesubstrate 16.

Examples of a method of preparing an inorganic layer formed of a carbide(carbon material) include a method of coating a resin compositionincluding a resin component such as a phenol resin on the first glasssubstrate 12 and carrying out a sintering process to performcarbonization.

Regarding manufacturing conditions, the optimum conditions areappropriately selected according to the material to be used.

(Laminating Step)

In the laminating step, the substrate 16 is laminated on the surface ofthe adhesive layer 14 obtained in the adhesive layer forming stepdescribed above to obtain the laminate 100 provided with the first glasssubstrate 12, the adhesive layer 14, and the substrate 16 in this order.

The method of laminating the substrate 16 on the adhesive layer 14 isnot particularly limited, and it is possible to adopt a known method.

Example thereof include a method in which the substrate 16 is laminatedon the surface of the adhesive layer 14 in a normal pressureenvironment. Here, as necessary, after laminating the substrate 16 onthe surface of the adhesive layer 14, the substrate 16 may bepressure-bonded to the adhesive layer 14 by using a roll or a press.Bubbles inserted between the adhesive layer 14 and the layer of thesubstrate 16 are comparatively easily removed by pressure bonding byrolling or pressing, which is preferable.

Press bonding by a vacuum lamination method or a vacuum press method ismore preferable because the insertion of bubbles is suppressed and goodadhesion is secured. By pressure bonding under vacuum, even in a casewhere minute bubbles remain, the heating does not cause the bubbles togrow and there is also an advantage in that distortion defects of thesubstrate 16 are not easily generated.

When laminating the substrate 16, it is preferable to sufficiently washthe surface of the substrate 16 in contact with the adhesive layer 14and carry out lamination in an environment with high cleanness. Thehigher the degree of cleanness, the better the flatness of the substrate16, which is preferable.

Here, after laminating the substrates 16, a pre-annealing treatment (aheat treatment) may be carried out as necessary. By performing thepre-annealing treatment, the adhesion of the laminated substrate 16 tothe adhesive layer 14 is improved and it is possible to obtain anappropriate peel strength (y) and, during the member forming stepdescribed below, positional shifting or the like of the member for anelectronic device is unlikely to occur, and the productivity of theelectronic device is improved.

(Laminate)

The laminate of the present invention (the laminate 100 of the firstembodiment and the laminate 110 of the second embodiment describedabove) are able to be used for various purposes, and example thereofincludes a purpose for manufacturing display device panels, PV, thinfilm secondary batteries, or electronic components such as asemiconductor wafer on which a circuit is formed on a surface, and thelike. Here, in such a purpose, the laminate 100 is exposed (for example,for 20 minutes or more) to high temperature conditions (for example,500° C. or more) in many cases. In other words, in many cases, a stephaving a process temperature of 500° C. or more is included when formingan electronic device.

Here, display device panels include an LCD, an OLED, electronic paper, aplasma display panel, a field emission panel, a quantum dot LED panel, aMEMS (Micro Electro Mechanical Systems) shutter panel, and the like.

<Electronic Device and Manufacturing Method Thereof>

In the present invention, an electronic device (also referred to belowas “a member-attached-substrate” as appropriate) including a substrateand a member for an electronic device is manufactured by using thelaminate described above.

A detailed description will be given below of a method for manufacturingan electronic device using the laminate having an adhesive layerdescribed above.

The method for manufacturing an electronic device is not particularlylimited, but from the viewpoint of excellent productivity of theelectronic device, a method of manufacturing a member for an electronicdevice-attached-laminate by forming a member for an electronic device onthe substrate in the laminate and separating an electronic device (amember-attached-substrate) and a carrier substrate from the obtainedmember for an electronic device-attached-laminate, with the substrateside interface of the adhesive layer as a peeling surface, ispreferable.

The step of forming a member for an electronic device on a substrate inthe laminate to manufacture a member for an electronicdevice-attached-laminate will be referred to below as a member formingstep, and a step of separating a member-attached-substrate and thecarrier substrate from the member for an electronicdevice-attached-laminate, with the substrate side interface of theadhesive layer as a peeling surface, will be referred to as a separatingstep.

A detailed description will be given below of the materials used in eachstep and the order thereof.

(Member Forming Step)

The member forming step is a step of forming a member for an electronicdevice on the substrate 16 in the laminate 100 obtained in thelaminating step. More specifically, as illustrated in (A) of FIG. 4, amember for an electronic device 20 is formed on the second main surface16 b (exposed surface) of the substrate 16 to obtain a member for anelectronic device-attached-laminate 22.

First, a detailed description will be given of the member for anelectronic device 20 used in this step, and then a detailed descriptionwill be given of the order of steps.

(Member for Electronic Device (Functional Element))

The member for an electronic device 20 is a member formed on thesubstrate 16 in the laminate 100 and constituting at least a part of theelectronic device. More specifically, examples of the member for anelectronic device 20 include display device panels, solar cells, thinfilm secondary batteries, or members used for an electronic componentsuch as a semiconductor wafer on which a circuit is formed on thesurface (for example, a member for a display device, a member for asolar cell, a member for a thin film secondary battery, and a circuitfor an electronic component).

Examples of members for solar cell include, in silicon type ones, atransparent electrode such as a tin oxide of a positive electrode, asilicon layer represented by a p layer/i layer/n layer, a metal of anegative electrode, and the like, and other examples include varioustypes of member corresponding to compound types, dye sensitizationtypes, quantum dot types, and the like.

In addition, examples of a member for a thin film secondary batteryinclude, in lithium ion type ones, transparent electrodes such as ametal or a metal oxide of a positive electrode and negative electrode, alithium compound of an electrolyte layer, a metal of a currentcollecting layer, a resin as a sealing layer, and the like and otherexamples include various other members corresponding to nickel hydrogentypes, polymer types, ceramic electrolyte types, and the like.

In addition, examples of circuits for electronic components include, forCCD and CMOS, metal conductive portions, silicon oxide or siliconnitride of insulating portions, and the like, and other examples includevarious sensors such as pressure sensors and acceleration sensors,various members corresponding to rigid printed substrates, flexibleprinted substrates, rigid flexible printed substrates, and the like.

Here, the member for an electronic device 20 preferably includeslow-temperature polysilicon (LTPS). That is, in the present memberforming step, it is preferable to include a step of manufacturinglow-temperature polysilicon. In particular, it is more preferable thatthe present member forming step includes a step of manufacturing a thinfilm transistor including low-temperature polysilicon.

Low-temperature polysilicon is polysilicon obtained by applyingcrystallization energy by laser annealing, furnace annealing, or thelike with using amorphous silicon as a precursor and crystallizing thesilicon. In the process of manufacturing such low-temperaturepolysilicon, the amorphous silicon is heated to 450° C. or more in manycases, in other words, the process temperature is 450° C. or more inmany cases.

In addition, in a case where the electronic device is an electronicdisplay, the resolution of the display is preferably 300 ppi (pixels perinch) or more in terms of using the carrier glass of the presentinvention. It is more preferably 400 ppi or more, and even morepreferably 500 ppi or more.

(Order of Steps)

The method for manufacturing the member for an electronicdevice-attached-laminate 22 described above is not particularly limited,and the member for an electronic device 20 is formed on the second mainsurface 16 b of the substrate 16 of the laminate 100 by a conventionallyknown method according to the type of the component members of themember for an electronic device.

Here, the member for an electronic device 20 may not be the entirety ofthe member finally formed on the second main surface 16 b of thesubstrate 16 (referred to below as “all members”), but may be a part ofall of the members (referred to below as a “partial member”). It is alsopossible to make a partial member-attached-substrate peeled from theadhesive layer 14 to be an all members-attached-substrate (correspondingto an electronic device to be described below) in subsequent steps.

In addition, another member for an electronic device may be formed onthe peeling surface (first main surface 16 a) of the allmembers-attached-substrate peeled from the adhesive layer 14. Inaddition, it is also possible to manufacture an electronic device byassembling the all members-attached-laminate and then peeling thecarrier substrate 10 from the all members-attached-laminate.Furthermore, it is also possible to manufacture amember-attached-substrate having two glass substrates by assembling twoall members-attached-laminates and then peeling two carrier substrates10 from the all members-attached-laminates.

For example, taking the case of manufacturing an OLED as an example, inorder to form an organic EL structure on the surface (corresponding tothe second main surface 16 b of the substrate 16) of the substrate 16 ofthe laminate 100 opposite to the adhesive layer 14 side, various kindsof layer formations and treatments are carried out such as forming atransparent electrode, vapor-depositing a hole injecting layer, a holetransporting layer, a light emitting layer, an electron transportinglayer, or the like on the surface on which the transparent electrode isformed, forming a back electrode, and sealing using a sealing plate.Specific examples of these layer formations and treatments include filmformation treatments, vapor deposition treatments, adhesion treatment ofa sealing plate, and the like.

In addition, for example, in the case of manufacturing a TFT-LCD, thereare various types of steps such as a TFT forming step of forming a thinfilm transistor (TFT) by forming a pattern on a metal film, a metaloxide film, or the like formed by a typical film formation method suchas a CVD method or a sputtering method using a resist solution on thesecond main surface 16 b of the substrate 16 of the laminate 100, a CFforming step of forming a color filter (CF) by using a resist solutionfor pattern forming on the second main surface 16 b of the substrate 16of another laminate 100, a bonding step of laminating theTFT-attached-laminate obtained in the TFT forming step and theCF-attached-laminate obtained in the CF forming step, and the like.

In the TFT forming step and the CF forming step, the TFT and CF areformed on the second main surface 16 b of the substrate 16 by usingwell-known photolithography techniques, etching techniques, or the like.Here, a resist solution is used as a coating solution for patternformation.

The second main surface 16 b of the substrate 16 may be cleaned beforeforming the TFT or the CF, if necessary. As a cleaning method, it ispossible to use well-known dry cleaning or wet cleaning.

In the bonding step, the thin film transistor forming surface of theTFT-attached-laminate and the color filter forming surface of theCF-attached-laminate are made to face each other and bonded together byusing a sealing agent (for example, an ultraviolet curable sealant forcell formation). Thereafter, the liquid crystal material is injectedinto the cell formed by the TFT-attached-laminate and theCF-attached-laminate. Examples of a method for injecting the liquidcrystal material include a reduced pressure injection method and adropping injection method.

(Separating Step)

As illustrated in (B) of FIG. 4, the separating step is a step ofseparating the substrate 16 (member-attached-substrate) on which themember for an electronic device 20 is laminated and the carriersubstrate 10 from the member for an electronic device-attached-laminate22 obtained in the member forming step, with the interface between theadhesive layer 14 and the substrate 16 as the peeling surface, so as toobtain a member-attached-substrate (electronic device) 24 including themember for an electronic device 20 and the substrate 16.

In a case where the member for an electronic device 20 on the substrate16 at the time of peeling is a part of the formation of all thecomponent members needed, it is also possible to form the remainingcomponent members on the substrate 16 after separation.

The method of peeling the substrate 16 and the carrier substrate 10 isnot particularly limited. Specifically, for example, it is possible toinsert a sharp cutter-like object into the interface between thesubstrate 16 and the adhesive layer 14 to give a peeling trigger, andthen a mixed fluid of water and compressed air is blown therein to carryout the peeling.

Preferably, the member for an electronic device-attached-laminate 22 isplaced on a platen with the carrier substrate 10 thereof being on theupper side and the member for an electronic device 20 side being on thelower side, the member for an electronic device 20 side is vacuumadsorbed on the platen (in a case where the carrier substrates arelaminated on both sides, this is carried out sequentially), and, in thisstate, the cutter first enters into the interface between the substrate16 and the adhesive layer 14. Thereafter, the carrier substrate 10 sideis adsorbed by a plurality of vacuum suction pads, and the vacuumsuction pads are raised in order from the vicinity of the place wherethe cutter is inserted. Then, an air layer is formed at the interfacebetween the adhesive layer 14 and the substrate 16 or on a cohesivefailure surface of the adhesive layer 14, and the air layer spreads overthe interface or the entire face of the cohesive failure surface, sothat it is possible to easily peel the carrier substrate 10.

In addition, it is possible to laminate the carrier substrate 10 with anew glass substrate to manufacture the laminate 100 of the presentinvention.

Here, when separating the member-attached-substrate 24 from the memberfor an electronic device-attached-laminate 22, controlling the sprayingby the ionizer and the humidity makes it possible to further suppressthe fragments of the adhesive layer 14 from being electrostaticallyattracted to the member-attached-substrate 24.

The method for manufacturing the member-attached-substrate 24 describedabove is suitable for manufacturing a small-sized display device usedfor a mobile terminal such as a mobile phone or a PDA. The displaydevice is mainly an LCD or OLED, and LCDs include TN type, STN type, FEtype, TFT type, MIM type, IPS type, VA type, and the like. Basically, itcan be applied to either case of display devices of passive drive typeor active drive type.

Examples of the member-attached-substrate 24 manufactured by the methoddescribed above include a panel for a display device having a glasssubstrate and a member for a display device, a solar cell having a glasssubstrate and a member for a solar cell, a thin film secondary batteryhaving a glass substrate and a member for a thin film secondary battery,an electronic part having a glass substrate and a member for anelectronic device, and the like. The panel for a display device includesa liquid crystal panel, an organic EL panel, a plasma display panel, afield emission panel, and the like.

Examples

A detailed description will be given below of the present invention withreference to Examples and the like, but the present invention is notlimited by these examples.

In the following Examples and Comparative Examples, the first glasssubstrates 1 to 12 manufactured in the following order were used. Thefirst glass substrates 5, 6 and 9 are Examples, and the first glasssubstrates 1 to 4, 7, 8, and 10 to 12 are Comparative Examples.

(Manufacture of First Glass Substrate)

Table 1 is a table showing the compaction and the like of glasssubstrates having 12 compositions. Materials for each component wereprepared to have the target compositions shown below and dissolved at atemperature of 1500° C. to 1600° C. by using a platinum crucible toobtain molten glass. During the dissolution, the glass was homogenizedby stirring using a platinum stirrer. Next, the molten glass was pouredout, formed into a plate shape having a plate thickness of 0.3 mm, andthen gradually cooled to manufacture a first glass substrate. Here, asthe gradual cooling conditions, cooling was performed at an averagecooling rate (° C./min) described in Table 1.

The Young's modulus was measured by an ultrasonic pulse method on aglass having a thickness of 0.5 to 10 mm according to the method set outin JIS Z 2280 (1993).

According to JIS-Z 2244; 2009, the Vickers hardness was measured byusing MVK-H100 manufactured by Akashi, with a test force of 0.9807 N anda pushing time of 15 seconds.

For the ultraviolet transmittance, the transmittance at a wavelength of300 nm was measured on a glass of 0.5 mm thickness optically polished onboth sides, by using an ultraviolet-visible-near-infraredspectrophotometer U4100 manufactured by Hitachi High-Tech ScienceCorporation.

TABLE 1 Number of First Glass Substrate 1 2 3 4 5 6 7 8 9 10 11 12Composition SiO₂ 59.6 59.6 59.6 59.6 62.1 62.1 62.1 62.1 61.3 61.3 61.361.3 (mass %) Al₂O₃ 17.2 17.2 17.2 17.2 19.0 19.0 19.0 19.0 19.8 19.819.8 19.8 B₂O₃ 7.7 7.7 7.7 7.7 2.6 2.6 2.6 2.6 1.3 1.3 1.3 1.3 MgO 3.33.3 3.3 3.3 2.0 2.0 2.0 2.0 5.6 5.6 5.6 5.6 CaO 4.1 4.1 4.1 4.1 4.1 4.14.1 4.1 4.6 4.6 4.6 4.6 SrO 7.7 7.7 7.7 7.7 2.3 2.3 2.3 2.3 6.9 6.9 6.96.9 BaO 0.1 0.1 0.1 0.1 7.6 7.6 7.6 7.6 0.1 0.1 0.1 0.1 MgO + CaO +SrO + BaO 15.1 15.1 15.1 15.1 16.0 16.0 16.0 16.0 17.1 17.1 17.1 17.1Manufacturing Average Cooling Rate 50 300 400 500 50 300 400 500 50 300400 500 conditions (° C./min) Physical Strain point (° C.) 670 670 670670 733 733 733 733 715 715 715 715 property values Compaction (ppm) 164272 291 306 44 77 83 88 46 81 87 92 Young's Modulus (GPa) 77 77 77 77 7878 78 78 85 85 85 85 Vickers hardness 570 570 570 570 590 590 590 590620 620 620 620 Transmittance (300 nm) (%) 40 40 40 40 70 70 70 70 70 7070 70 (plate thickness 0.5 mm)

Measurement of the strain point was carried out by the method describedabove.

In addition, the compaction in the table described above shows thecompaction (shrinkage) in a case where the temperature is raised fromroom temperature at 100° C./hour, heat treatment is performed at 600° C.for 80 minutes, and cooling to room temperature is performed at 100°C./hour. This shows calculated values obtained by the method describedbelow, but the measurement values measured by the method described abovewere also almost the same as the calculated values in the above table.

(Calculation Method of Compaction)

The calculation of compaction C was obtained by using the followingformula that expresses the structural relaxation of glass and by makingminute temperature changes and performing successive calculations. Asthe various parameters (β, τ), ones obtained by actual measurement usingthe glass of the composition were used.

(V)(ξ)−V ₀)/(V _(∞) −V ₀)=exp[−(ξ/τ)^(β)]

C=10⁶ ×ΔL/L=10⁶×[1−(V(ξ)/V ₀)^(1/3)]

Here, V₀ is a molar volume of the glass at processing time 0, V_(∞) isan equilibrium molar volume at the treatment temperature, V(ξ) is amolar volume of the glass at a conversion time ξ, C is the compaction(unit: ppm), L is the glass length, ΔL is a change amount of the glasslength before and after treatment, τ is a relaxation time constant, andβ is a parameter showing a spread of the relaxation time constant.

(Measurement of Compaction of Glass Substrate During a Plurality ofTimes of Heat Treatment)

Table 2 is a table showing the results of measurement of compaction whensubjecting the glass substrate of Table 1 to a plurality of times (threetimes) of heat treatment. By using the first glass substrates 1 to 12,the compaction of the glass substrate was calculated after each heattreatment when the heat treatment under the following heating conditionswas performed a plurality of times. The column of “first time” shows thecompaction (ppm) of the glass substrate after performing the followingheat treatment once. The column of “second time” shows the compactionafter the glass substrate subjected to the first heat treatment wascooled to room temperature and then subjected to the second heattreatment. The column of “third time” shows the compaction after theglass substrate subjected to the second heat treatment was cooled toroom temperature and then subjected to the third heat treatment.

(Heat Treatment)

The glass substrate was subjected to temperature raising from roomtemperature to 450° C. in 5 minutes, held at 450° C. for 20 minutes, andthen cooled to room temperature in 5 minutes, and furthermore, the glasssubstrate was subjected to temperature raising from room temperature to600° C. in 5 minutes, held at 600° C. for 5 minutes, and then cooled toroom temperature in 5 minutes.

As shown in Table 2, in a case where the first glass substrate was 1 to4, since the “compaction (ppm) at 600° C. for 80 minutes” in Table 1 wasas large as 150 ppm or more, the compaction value in the electronicdevice forming step was 10 ppm or more and the difference ΔC₂₋₁ betweenthe compaction value at the initial heat treatment and the compactionvalue at the second heat treatment was 10 ppm or more, which is a greatchange, in all cases, which was not suitable as the substrate. Inaddition, in Table 1, in a case where the “compaction (ppm) at 600° C.for 80 minutes” was 80 ppm or less (first glass substrates 5, 6 and 9),it was confirmed that the difference ΔC₂₋₁ between the compaction valueat the initial heat treatment and the compaction value at the secondheat treatment and the difference ΔC₃₋₂ between the compaction value atthe second heat treatment and that at the third heat treatment were bothas small as 6 ppm or less.

(Manufacture of Electronic Device)

Alkenyl group-containing organopolysiloxane (number average molecularweight: 2000, number of alkenyl groups: 2 or more) (100 parts by mass)and hydrogen polysiloxane (number average molecular weight: 2000, numberof hydrosilyl groups: 2 or more) (6.7 parts by mass) were blended. Here,the blending molar ratio (number of moles of hydrosilyl group/number ofmoles of alkenyl group) of the alkenyl groups in the alkenylgroup-containing organopolysiloxane and the hydrosilyl groups in thehydrogen polysiloxane was 0.4/1. Furthermore, a catalyst (platinumcatalyst) was added in an amount of 300 ppm based on the total mass (100parts by mass) of the alkenyl group-containing organopolysiloxane andthe hydrogen polysiloxane. This solution is referred to as curable resincomposition X. This curable resin composition X was coated on the firstmain surface of the first glass substrate 1 by using a die coater toprovide a layer including the uncured alkenyl group-containingorganopolysiloxane and hydrogen polysiloxane on the first glasssubstrate 1.

Next, after heating in the air at 140° C. for 3 minutes, curing wascarried out by heating in air at 230° C. for 20 minutes to form asilicone resin layer with a thickness of 10 μm on the first main surfaceof the first glass substrate 1. The flatness of the silicone resin layerwas good.

Thereafter, the second glass substrate and the silicone resin layersurface were bonded together by vacuum pressing at room temperature toobtain a glass laminate A.

Here, a glass plate (length 200 mm, width 200 mm, plate thickness 0.2mm, linear expansion coefficient 38×10⁻⁷/° C., trade name “AN 100”manufactured by Asahi Glass Company, Ltd.) formed of alkali-freeborosilicate glass was used as the second glass substrate.

In the obtained glass laminate A, the first glass substrate and thesecond glass substrate were in close contact with the silicone resinlayer without generating bubbles, and there were no distortion defects.In addition, in the glass laminate A, the peel strength at the interfacebetween the silicone resin layer and the layer of the first glasssubstrate was greater than the peel strength at the interface betweenthe layer of the second glass substrate and the silicone resin layer.

Next, an electronic device was manufactured on the second glasssubstrate of the glass laminate A according to the following method.

As the electronic device manufacturing method, an LTPS process using anexcimer laser annealing method was used. First, a protective layer wasformed on the second glass substrate, and then a film of amorphoussilicon was formed. A dehydrogenating step, laser irradiation, and anactivating step were performed, various wirings such as a gateelectrode, and a source and a drain electrodes were formed andpatterned, and an interlayer insulating film or the like was formed toform a thin film transistor circuit.

Here, a step with a manufacturing process temperature of 500° C. or morewas included in the manufacturing steps of the electronic device.

Then, while a stainless-steel cutter having a thickness of 0.1 mm wasinserted into the interface between the second glass substrate and thesilicone resin layer at one corner portion of four corner portions ofthe glass laminate A on which the electronic device was manufactured, toform peeling cutaway portion, a vacuum suction pad was adsorbed to asurface which is not a peeling surface of the first glass substrate andan external force was applied in a direction in which the carriersubstrate and the electronic device (member for an electronicdevice-attached-second glass) separate from each other so as to separatethe carrier substrate and the electronic device without breaking. Here,the cutter was inserted while spraying static eliminating fluid from anionizer (manufactured by Keyence Corporation) onto the interface.Specifically, the vacuum suction pad was pulled up while continuouslyspraying the static elimination fluid from the ionizer toward the formedgap.

Here, the silicone resin layer was separated from the second glasssubstrate with the first glass substrate and, from the results, it wasconfirmed that the peel strength (x) at the interface between the layerof the first glass substrate and the silicone resin layer was higherthan the peel strength (y) at the interface between the silicone resinlayer and the second glass substrate.

Next, by using the recovered carrier substrate, the glass laminate A wasmanufactured according to the same procedure as described above, and anelectronic device was manufactured in accordance with the same procedureas described above.

This process was repeated twice to manufacture electronic devices.

Here, a plurality of glass laminates A were prepared and each of theabove treatments was carried out.

(Evaluation (Productivity))

A case where the manufacturing yield of the electronic device at thesecond and third use of the carrier substrate was equivalent to thefirst time was “A”, a case where the manufacturing yield was reduced,but fell within a practically acceptable range was “B”, and a case wherethe manufacturing yield dropped greatly and was not acceptable forpractical use was “C”.

The (Evaluation (Productivity)) described above was carried outaccording to the above procedure by using the first glass substrates 2to 12 in place of the first glass substrate 1.

TABLE 2 Compaction (ppm) at Compaction 600° C. for First Second ThirdPro- 80 min time time time ductivity First glass substrate 1 164 17.814.6 12.5 C First glass substrate 2 272 42.7 26.4 21.6 C First glasssubstrate 3 291 47.7 28.5 23.2 C First glass substrate 4 306 51.8 30.324.5 C First glass substrate 5 44 4.6 3.5 2.9 A First glass substrate 677 12.8 6.8 5.3 B First glass substrate 7 83 14.5 7.4 5.8 C First glasssubstrate 8 88 15.9 7.9 6.1 C First glass substrate 9 46 4.6 3.6 3.0 AFirst glass substrate 10 81 14.1 7.2 5.5 C First glass substrate 11 8716.1 7.8 6.0 C First glass substrate 12 92 17.7 8.3 6.3 C

As shown in the above Table 2, it was confirmed that excellent effectswere able to be obtained in a case where the first glass substrates 5, 6and 9 having compaction (ppm) of 80 ppm or less are used. In particular,it was confirmed that the effect was superior in a case where thecompaction was 70 ppm or less.

While the present invention has been described in detail and withreference to specific embodiments thereof, it will be apparent to oneskilled in the art that various changes and modifications can be madetherein without departing from the intention and scope of the presentinvention. The present application is based on a Japanese patentapplication filed on Jul. 3, 2015 (Application No. 2015-134697), thewhole thereof being incorporated herein by reference.

REFERENCE SIGNS LIST

-   -   10 CARRIER SUBSTRATE    -   12, 112 FIRST GLASS SUBSTRATE    -   14 ADHESIVE LAYER    -   16, 116 SUBSTRATE    -   20 MEMBER FOR ELECTRONIC DEVICE    -   22 MEMBER FOR ELECTRONIC DEVICE-ATTACHED-LAMINATE    -   24 MEMBER-ATTACHED-SUBSTRATE (ELECTRONIC DEVICE)    -   100, 110 LAMINATE

1. A carrier substrate to be used, when manufacturing a member for anelectronic device on a surface of a substrate, by being bonded to thesubstrate, the carrier substrate comprising at least a first glasssubstrate, wherein the first glass substrate has a compaction describedbelow of 80 ppm or less: compaction: a shrinkage in a case of subjectingthe first glass substrate to a temperature raising from a roomtemperature at 100° C./hour and to a heat treatment at 600° C. for 80minutes, and then to a cooling to the room temperature at 100° C./hour.2. The carrier substrate according to claim 1, wherein the compaction is70 ppm or less.
 3. The carrier substrate according to claim 1, whereinthe first glass substrate has a strain point of 700° C. or more.
 4. Thecarrier substrate according to claim 1, wherein the first glasssubstrate comprises a glass comprising, in terms of mass percentagesbased on oxides, the following: SiO₂: 50% to 73%, Al₂O₃: 10.5% to 24%,B₂O₃: 0% to 5%, MgO: 0% to 10%, CaO: 0% to 14.5%, SrO: 0% to 24%, BaO:0% to 13.5%, and MgO+CaO+SrO+BaO: 8% to 29.5%.
 5. The carrier substrateaccording to claim 1, further comprising an adhesive layer arranged onthe first glass substrate.
 6. A laminate comprising: the carriersubstrate according to claim 1; and a substrate arranged on the carriersubstrate.
 7. The laminate according to claim 6, wherein the substrateis a second glass substrate.
 8. A method for manufacturing an electronicdevice, comprising: a member forming step of forming a member for anelectronic device on a surface of the substrate of the laminateaccording to claim 6 to obtain a member for an electronicdevice-attached-laminate; and a separating step of removing the carriersubstrate from the member for an electronic device-attached-laminate toobtain an electronic device having the substrate and the member for anelectronic device.
 9. The method for manufacturing an electronic deviceaccording to claim 8, wherein the member for an electronic devicecomprises a low-temperature polysilicon (LTPS).
 10. The method formanufacturing an electronic device according to claim 9, furthercomprising a step having a process temperature of 450° C. or more informing the member for an electronic device.